C

You have to give Christopher Landon credit for trying something different, at least. The first “Happy Death Day” was a wacky horror comedy, a version of “Scream” told through the scrim of “Groundhog Day.” “Scream” remains an ingredient in the sequel, “Happy Death Day 2U,” but this time around it’s mixed with a strong dose of “Back to the Future” as well as the “Groundhog” repetition formula—the script explicitly acknowledges the debt. The problem is that the combination becomes unwieldy; simply put, the movie is a mess, though an energetic one.

At first it appears that Landon intends to go the most predictable route. The initial sequences of “2U” transpose the it’s-happening-again business to a secondary character from the first movie, Ryan Phan (Phi Vu), the roommate of Carter Davis (Israel Broussard), the amiably geeky fellow whose niceness mellowed sorority mean girl Tree (Jessica Rothe) as she went through her ordeal of being repeatedly stalked and killed by a masked figure.

But the script, written by Landon himself this time around, soon puts Tree back at the center of things. It seems that Ryan, whose scientific brilliance the first movie hardly suggested, has been working with his lab buddies Samar (Suraj Sharma) and Dre (Sarah Yarkin) on a device that switches dimensions, one that presumably had a role in Tree’s dilemma in the first place. His attempt to use it to fix his current problem lands her back in the repetitive loop from the previous movie, but with a twist: she’s now in an alternate (but parallel) world where Carter is the boyfriend of Tree’s sorority-house queen Danielle (Rachel Matthews), and Lori (Ruby Modine), the killer in the previous picture, is still alive. And she’s not the only person come back to life in this revised universe.

A chunk of “2U” is devoted to the die-and-die-again theme, and to unmasking who the killer in this new scenario might be. But frankly this “horror” portion of the movie is treated as farce more than quasi-thriller—Tree’s deaths are jokey suicides rather than murders—and when the killer is identified, the revelation comes as a damp squib, provoking little more than a “who cares?” although it’s dressed up with menace. Unlike the first picture, this one doesn’t even attempt to be scary.

That’s all part of the decision to emphasize the comedic aspect of “horror comedy.” Some of the humor is mildly amusing, but other bits fall flat. All of the material involving Steve Zissis as a dean who wants to shut down Ryan’s experiment, for example, is a bust—and there’s a good deal of it, including a protracted, thoroughly misguided, sequence in which Danielle is enlisted to divert his attention while Ryan and his cohorts get the apparatus operating again. Simply put, “2U” is a lot less funny than it wants to be.

There’s also an effort to recast the story in romantic and sentimental terms. Stuck in this new dimension, Tree is irritated to see Carter and Danielle as a couple, and although one thoroughly odd bit involving handsome boob Nick (Blaine Kern III) comes out of left field in that connection, the question of Tree’s feelings for him becomes an important factor in whether she’ll choose, in a pinch, to go back to her “real” world where they’re an item, since—for reasons that won’t be revealed here—there’s also an important reason for her to remain in the dimension where they’re not. This new dilemma for our heroine generates little tension or interest.

Finally, there’s the sci-fi aspect of the plot. Though, as in “Future,” it’s presented in comedic terms, all the pseudo-scientific blather bandied about has a deadening effect, and by introducing obstacle after obstacle to the machine functioning, the script wallows in the absurdity of the entire plot thread to the point of irritation.

In fairness one has to congratulate editor Ben Baudhuin for juggling all the different elements in Landon’s script as successfully as he has, just as one can commend Bill Boes’s production design (except for Ryan’s ridiculous-looking device) and Toby Oliver’s cinematography, both of which are much superior to what you usually encounter in a Blumhouse production. The cast certainly engage with the material enthusiastically. As in the previous picture, Rothe gives her all, which is considerable; and Broussard makes an engaging partner for her. Vu, who has a much bigger part to play this time around, is fine, although sometimes he skirts the line between deadpan and boring.

There’s every indication—including some obvious suggestions at the end of the picture—that Landon and Jason Blum hope that “Happy Death Day 2U” will be only part of a continuing franchise. It’s a question, however, whether fans will be happy with what is actually a pretty radical change from the previous picture—a new recipe that doesn’t work all that well.